Touch screen device

ABSTRACT

Disclosed is a touch screen device for accurately detecting a touch by using a touch pen without having a separate sensor provided in a touch panel. The touch screen device includes a touch screen including a plurality of touch electrodes, a touch driving circuit applying a touch electrode driving signal to the plurality of touch electrodes, and a touch pen receiving the touch electrode driving signal applied to the plurality of touch electrodes and transmitting a pen output signal, synchronized with the received touch electrode driving signal, to the touch screen.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of the Korean Patent Application No.10-2014-0196052 filed on Dec. 31, 2014 which is hereby incorporated byreference for all purposes as if fully set forth herein.

BACKGROUND

1. Field of the Invention

The present invention relates to a touch screen device. Moreparticularly, the present invention relates to a touch screen device foraccurately detecting a touch by using a touch pen even without aseparate sensor being provided in a touch panel.

2. Discussion of the Related Art

Examples of flat panel display devices, which display an image by usingdigital data, include liquid crystal display (LCD) devices using liquidcrystal, plasma display panels (PDPs) using discharging of an inert gas,organic light emitting diode (OLED) display devices using OLEDs, etc.

Recently, touch screen devices which are each implemented with a touchpanel added into a flat panel display device are being produced, andexamples of the touch screen devices include smartphones, smart books,etc. In the touch screen devices, writing or drawing may be performed byusing a touch pen as well as a human touch performed by a finger. Atouch input using the touch pen is more precise than an inputcorresponding to the human touch and thus enables precise writing anddrawing to be more easily performed.

In a related art touch screen device, a plurality of electrodes orsensors are separately provided in a touch panel so as to recognize atouch performed by a touch pen. Particularly, when a touch panel isimplemented as one body with a display panel, a plurality of electrodesand sensors are further provided, and for this reason, a manufacturingprocess becomes complicated, and the manufacturing cost increases.

SUMMARY

Accordingly, the present invention is directed to a touch screen devicethat substantially obviates one or more problems due to limitations anddisadvantages of the related art.

An aspect of the present invention is directed to a touch screen devicefor accurately detecting a touch by using a touch pen even without aseparate sensor being provided in a touch panel.

In addition to the aforesaid objects of the present invention, otherfeatures and advantages of the present invention will be describedbelow, but will be clearly understood by those skilled in the art fromdescriptions below.

Additional advantages and features of the invention will be set forth inpart in the description which follows and in part will become apparentto those having ordinary skill in the art upon examination of thefollowing or may be learned from practice of the invention. Theobjectives and other advantages of the invention may be realized andattained by the structure particularly pointed out in the writtendescription and claims hereof as well as the appended drawings.

To achieve these and other advantages and in accordance with the purposeof the invention, as embodied and broadly described herein, there isprovided a touch screen device including: a touch screen including aplurality of touch electrodes; a touch driving circuit applying a touchelectrode driving signal to the plurality of touch electrodes; and atouch pen receiving the touch electrode driving signal applied to theplurality of touch electrodes and transmitting a pen output signal,synchronized with the received touch electrode driving signal, to thetouch screen.

It is to be understood that both the foregoing general description andthe following detailed description of the present invention areexemplary and explanatory and are intended to provide furtherexplanation of the invention as claimed.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are included to provide a furtherunderstanding of the invention and are incorporated in and constitute apart of this application, illustrate embodiments of the invention andtogether with the description serve to explain the principle of theinvention. In the drawings:

FIG. 1 is a diagram illustrating a configuration of a touch screendevice according to an embodiment of the present invention;

FIG. 2 is a block diagram illustrating a display panel of the touchscreen device according to an embodiment of the present invention and acontroller thereof;

FIG. 3 is a waveform diagram showing time-division driving of thedisplay panel included in the touch screen device according to anembodiment of the present invention;

FIGS. 4A and 4B are block diagrams illustrating in detail a touch screenof the touch screen device according to an embodiment of the presentinvention and a touch controller thereof;

FIG. 5 is a diagram illustrating a modified example of the touch screenillustrated in FIG. 4A;

FIG. 6 is a waveform diagram showing a touch electrode driving signalsupplied to a touch detection electrode of the touch screen illustratedin FIG. 5;

FIG. 7 is a block diagram illustrating an internal structure of a touchpen according to an embodiment of the present invention;

FIG. 8 is a flowchart illustrating an operation of the touch penaccording to an embodiment of the present invention;

FIG. 9 is a driving waveform diagram showing a touch electrode drivingsignal and a pen output signal; and

FIG. 10 is a diagram describing an area where a first touch electrodedriving signal is used.

DETAILED DESCRIPTION OF THE INVENTION

Reference will now be made in detail to the exemplary embodiments of thepresent invention, examples of which are illustrated in the accompanyingdrawings. Wherever possible, the same reference numbers will be usedthroughout the drawings to refer to the same or like parts.

The terms described in the specification should be understood asfollows. As used herein, the singular forms “a”, “an” and “the” areintended to include the plural forms as well, unless the context clearlyindicates otherwise. The terms “first” and “second” are fordifferentiating one element from the other element, and these elementsshould not be limited by these terms. It will be further understood thatthe terms “comprises”, ‘comprising”, “has”, “having”, “includes” and/or“including”, when used herein, specify the presence of stated features,integers, steps, operations, elements, and/or components, but do notpreclude the presence or addition of one or more other features,integers, steps, operations, elements, components, and/or groupsthereof. The term “at least one” should be understood as including anyand all combinations of one or more of the associated listed items. Forexample, the meaning of “at least one of a first item, a second item,and a third item” denotes the combination of all items proposed from twoor more of the first item, the second item, and the third item as wellas the first item, the second item, or the third item. The term “on’should be construed as including a case where one element is formed at atop of another element and moreover a case where a third element isdisposed therebetween.

Hereinafter, an example of a touch screen device according to anembodiment of the present invention will be described in detail withreference to the accompanying drawings.

FIG. 1 is a diagram illustrating a configuration of a touch screendevice according to an embodiment of the present invention.

Referring to FIG. 1, the touch screen device according to an embodimentof the present invention may include a display panel 200, which has adisplay function and a detection function, and a touch pen 100 thatperforms a touch detection function according to a specific area beingtouched.

The display panel 200 may detect a touch which is performed by a fingerin addition to the touch pen 100, and may include a capacitive touchscreen integrated in the display panel 200. The touch screen may includea touch electrode (or a touch line) which is disposed on a glasssubstrate and is a separate element. Also, the touch screen may beimplemented in an in-cell type where a touch detection electrode and aconnection line thereof are formed in a process of forming a pixel arraywhich is used for the display panel 200 to display a screen. In thein-cell type, a supporting substrate may be omitted, and thus, thefinished display panel 200 may have the almost same thickness and weightas those of a display panel having an original screen display function.

The display panel 200 may be one of a liquid crystal panel, a fieldemission display panel, a plasma display panel, an OLED display panel,an electrophoresis display panel, etc. In embodiments to be describedbelow, the liquid crystal panel will be described. When the displaypanel 200 is implemented as the liquid crystal panel, a plurality ofelectrodes configuring a touch screen may be formed simultaneously witha process of forming a line of the liquid crystal panel.

According to the embodiments of the present invention, a conductive tipof the touch pen may be used as an element that receives a touchelectrode driving signal of the touch screen. Also, the conductive tipmay be used as an element that transmits a pen output signal generatedin the touch pen. Also, the touch pen may output the pen output signalin synchronization with the touch electrode driving signal of the touchscreen which is received by the touch pen.

Therefore, according to the embodiments of the present invention,whether a touch is performed by the touch pen is accurately detected inthe driving period of the touch screen, and thus, an accuracy of touchdetection increases. Accordingly, it is possible to implement ahigh-sensitivity input pen. Also, a linearity of touch detection ismaintained, and thus, touch performance is enhanced. Also, although aseparate electrode for driving the touch pen is not added into thedisplay panel, a high sensation of touch sensing is maintained, andthus, a structure is simplified.

The touch pen according to an embodiment of the present invention willbe described below with reference to FIGS. 7 to 10.

FIG. 2 is a block diagram illustrating a display panel of the touchscreen device according to an embodiment of the present invention and acontroller thereof.

Referring to FIG. 2, the display panel 200 of the touch screen deviceaccording to an embodiment of the present invention may be connected toa gate driving circuit 26 (30) and a data driving circuit 24 which areincluded in a pixel array driving circuit. Also, the display panel 200may be connected to a touch driving circuit 300 that is a touch screendriving circuit. The pixel array driving circuit and the touch screendriving circuit may be connected to a timing controller 22 and may beintegrated into a single module (not shown).

When the display panel 200 is the liquid crystal panel, the displaypanel 200 may include a liquid crystal layer disposed between twosubstrates. The substrates may each be manufactured as a glasssubstrate, a plastic substrate, a film substrate, or the like. A pixelarray disposed on a lower substrate of the display panel 200 may includea plurality of data lines, a plurality of gate lines intersecting thedata lines, and a plurality of pixels which are arranged in a matrixtype. The pixel array may further include a plurality of thin filmtransistors (TFTs) which are respectively formed in the plurality ofpixels defined by intersections of the data lines and the gate lines, aplurality of pixel electrodes for respectively charging the plurality ofpixels with data voltages, and a plurality of storage capacitors whichare respectively connected to the plurality of pixel electrodes to holdrespective pixel voltages.

The pixels of the display panel 200 may be respectively provided in aplurality of pixel areas defined by the data lines (D1 to Dm) and thegate lines (G1 to Gn) and may be arranged in the matrix type. A liquidcrystal cell of each of the pixels may adjust a transmission amount ofincident light according to a voltage difference between a data voltageapplied to a corresponding pixel electrode and a common voltage appliedto a corresponding common electrode. Each of the TFTs may be turned onin response to a gate pulse supplied through a corresponding gate lineand may supply a data voltage, supplied through a corresponding dataline, to a pixel electrode of a corresponding liquid crystal cell. Thecommon electrode may be disposed on a lower substrate or an uppersubstrate.

The upper substrate of the display panel 200 may include a black matrix,a color filter, etc. A polarizer may be attached to each of the uppersubstrate and the lower substrate of the display panel 200, and analignment layer for adjusting a pre-tilt angle of liquid crystal may bedisposed on an inner surface contacting the liquid crystal. A spacer formaintaining a cell gap of the liquid crystal cell may be disposedbetween the upper substrate and the lower substrate of the display panel200.

The display panel 200 may be implemented in a well-known liquid crystalmode such as a twisted nematic (TN) mode, a vertical alignment (VA)mode, an in-plane switching (IPS) mode, a fringe field switching (FFS)mode, or the like.

A backlight unit may be optionally disposed on a rear surface of thedisplay panel 200. The backlight unit may be implemented as an edge typebacklight unit or a direct type backlight unit and may irradiate lightonto the display panel 200.

The data driving circuit 24 may convert digital video data RGB, inputfrom the timing controller 22, into analog positive/negative gammacompensation voltages to generate data voltages. The data drivingcircuit 24 may respectively supply the data voltages to the data linesaccording to control by the timing controller 22 and may invertpolarities of the data voltages.

The gate driving circuit 26 (30) may sequentially supply the gate pulse(or a scan pulse), synchronized with the data voltages, to the gatelines to select lines of the display panel 200 in which the datavoltages are respectively written. The gate driving circuit 26 (30) mayinclude a level shifter 26 and a shift register 30. The shift register30 may be directly provided on the substrate of the display panel 200 ina gate-in panel (GIP) type.

The level shifter 26 may be provided on a printed circuit board (PCB) 20electrically connected to the lower substrate of the display panel 200.The level shifter 26 may output clock signals that swing between a gatehigh voltage VGH and a gate low voltage VGL according to control by thetiming controller 22. The gate high voltage VGH may be set as a voltageequal to or higher than a threshold voltage of a thin film transistor(TFT) which is formed in the pixel array of the display panel 200. Thegate low voltage VGL may be set as a voltage lower than the thresholdvoltage of the TFT which is formed in the pixel array of the displaypanel 200. The level shifter 26 may output a start pulse VST and a clocksignal CLK which swing between the gate high voltage VGH and the gatelow voltage VGL in response to a reference start signal ST, a firstclock GCLK, and a second clock MCLK which are input from the timingcontroller 22. Phases of the clock signals CLK output from the levelshifter 26 may be sequentially shifted, and the phase-shifted clocksignals CLK may be transferred to a shift register 30 which is providedin the display panel 200.

The shift register 30 may start to perform synchronization in responseto the start pulse VST input from the level shifter 26, shift an outputin response to the clock signals CLK, and sequentially supply the gatepulse to the gate lines of the display panel 200.

The timing controller 22 may supply digital video data RGB, input froman external host system, to a plurality of integrated circuits (ICs)included in the data driving circuit 24. The timing controller 22 mayreceive timing signals such as a vertical sync signal Vsync, ahorizontal sync signal Hsync, a data enable signal DE, and a clock togenerate a plurality of timing control signals for controlling operationtimings of the data driving circuit 24 and the gate driving circuit 26(30). The timing controller 22 or the host system may generate a syncsignal SYNC for controlling operation timings of a pixel array drivingcircuit and the touch driving circuit 300.

The touch driving circuit 300 may apply the touch electrode drivingsignal to a plurality of touch electrodes (or lines) and may count adriving signal voltage change of after and before a touch is performed,or may count a rising or falling edge delay time of a driving signal,thereby sensing a capacitance change. The touch driving circuit 300 mayconvert sensing data, received from a capacitance of the touch screen,into digital data to output touch raw data. Also, the touch drivingcircuit 300 may execute a predetermined touch recognition algorithm andmay analyze the touch raw data to detect a touch (or proximity) input.

FIG. 3 is a waveform diagram showing time-division driving of thedisplay panel included in the touch screen device according to anembodiment of the present invention.

As shown in FIG. 3, the display panel 200 and the touch screen may betime-division driven. That is, one frame period may be time-divided intoa pixel array driving period T1 and a touch screen driving period T2.

Vsync refers to a first vertical sync signal which is input to thetiming controller 22, and SYNC refers to a second vertical sync signalwhich is input to the touch driving circuit 300. The timing controller22 may modulate the first vertical sync signal Vsync input from the hostsystem to generate the second vertical sync signal SYNC, for definingthe pixel array driving period T1 and the touch screen driving period T2in one frame period. Alternatively, the host system may generate thesecond vertical sync signal SYNC, and the timing controller 22 maycontrol the pixel array driving period T1 and the touch screen drivingperiod T2 in response to the second vertical sync signal SYNC input fromthe host system. That is, one of the timing controller 22 and the hostsystem may time-divide the one frame period into the pixel array drivingperiod T1 and the touch screen driving period T2 to control theoperation timings of the pixel array driving circuit and the touchdriving circuit.

For example, when it is assumed that the display panel 200 is driven ata frequency of 60 Hz, 1/60 sec may be one frame period, which may bedivided into the pixel array driving period T1 and the touch screendriving period T2. As described above, the reason that pixel arraydriving and touch screen driving are time-division performed is becausewhen the pixel array and the touch screen are driven at the same time, adisplayed screen is not uniform due to severe driving interferencetherebetween, or an accuracy of touch detection is lowered.

During the pixel array driving period T1, the data driving circuit 24may respectively supply data voltages to the data lines according tocontrol by the timing controller 22, and the gate driving circuit 26(30) may sequentially supply the gate pulse, synchronized with the datavoltages, to the gate lines. The touch driving circuit 300 may notsupply the touch electrode driving signal to the touch electrodes duringthe pixel array driving period T1.

Moreover, during the touch screen driving period T2, the pixel arraydriving circuit may not be driven, and the touch driving circuit 300 maybe driven. Therefore, during the touch screen driving period T2, thetouch driving circuit 300 may supply the touch electrode driving signalto the touch electrodes to detect a position of a touch (or proximity)input.

FIGS. 4A and 4B are block diagrams illustrating in detail a touch screenof the touch screen device according to an embodiment of the presentinvention and a touch controller thereof.

As illustrated in FIG. 4A, in the touch screen of the touch screendevice according to an embodiment of the present invention, a pluralityof touch electrodes COM1 to COMn for detecting a position of an inputtool may be provided in the display panel 200 in an in-cell type.

For example, when the display panel 200 is a liquid crystal panel wherea pixel array is included in a lower substrate and a color filter arrayis included in an upper substrate, the touch electrodes may be providedon the lower substrate along with the pixel array, or may be provided onthe color filter array. Also, the touch electrodes may be used bypatterning a common electrode which is formed on the lower substrate orthe upper substrate. For example, if touch electrodes COM1 to COMn areformed by patterning the common electrode, a common voltage may beuniformly applied to the touch electrodes in order for the touchelectrodes to act as the common electrode in pixel array driving.

The touch electrodes COM1 to COMn may be connected to a plurality ofsensing lines S1 to Sn in one-to-one correspondence relationship, andthe sensing lines S1 to Sn may be connected to the touch driving circuit300.

The touch driving circuit 300, as illustrated in FIG. 4B, may include areception system circuit group which includes a reception amplifier 30,an analog-to-digital conversion circuit 32, a detector 34, a memory 36,and a position detector 38.

Moreover, the reception system circuit group may be connected to acentral processing unit (CPU) 40 connected to an external host. Also,the CPU 40 may be connected to a controller 42 that overall controls atouch operation, and the controller 42 may be connected to a drivingsignal generator 46, whereby a touch electrode driving signal Tsgenerated by an oscillator 44 may be supplied to the touch electrodesCOM1 to COMn through the sensing lines S1 to Sn.

A touch screen illustrated in the drawing may have a self-capacitancetype, and the touch electrodes COM1 to COMn may be used for all of adriving signal applying operation and a reception signal detectingoperation.

A size of each of the touch electrodes COM1 to COMn may be larger thanthat of each of a plurality of pixels, and for example, each of thetouch electrodes COM1 to COMn may be formed in a size overlapping aplurality of pixels. Also, the touch electrodes COM1 to COMn may each beformed of a transparent conductive material and thus do not reduce anaperture ratio during a display period of pixel array driving.

A common voltage source (not shown) may supply a common voltage Vcom tothe touch electrodes COM1 to COMn through the sensing lines S1 to Snduring the pixel array driving period T1. Therefore, the touchelectrodes COM1 to COMn may act as the common electrode during the pixelarray driving period T1. To this end, the touch electrodes COM1 to COMnmay be connected to a selection circuit (not shown), which may beconnected to the common voltage source and the touch driving circuit300.

The touch driving circuit 300 may be disabled during the pixel arraydriving period T1, and during the touch screen driving period T2, thetouch driving circuit 300 may be enabled. Therefore, during only thetouch screen driving period T2, the touch driving circuit 300 maysimultaneously supply the touch electrode driving signal to the sensinglines S1 to Sn.

FIG. 5 is a diagram illustrating a modified example of the touch screenillustrated in FIG. 4A, and FIG. 6 is a waveform diagram showing a touchelectrode driving signal supplied to a touch detection electrode of thetouch screen illustrated in FIG. 5.

In a self-capacitive touch screen TSP, as illustrated in FIG. 5, inorder to reduce the number of signal application lines connected to thetouch driving circuit 300, a multiplexer 302 may be further connected toinput terminals of the touch electrodes COM1 to COMn, and a signal maybe applied to the sensing lines S1 to Sn through time division. Themultiplexer 302 may be provided as one or in plurality. For example, ifthe multiplexer 302 is a 1:k (where k is a natural number which is equalto or larger than two and is smaller than n) multiplexer, themultiplexer 302 may be connected to the touch driving circuit 300through n/k number of signal application lines. In this case, asillustrated in FIG. 6, the n touch electrodes COM1 to COMn may begrouped in units of k touch electrodes, and k number of touch electrodesmay receive k number of time-divided touch electrode driving signals Ts.

FIG. 7 is a block diagram illustrating an internal structure of a touchpen according to an embodiment of the present invention.

The touch pen used as a touch input device according to an embodiment ofthe present invention, as illustrated in FIG. 7, may include a housing180, a conductive tip 110 that protrudes to outside one side of thehousing 180, a switching unit 120 that is connected to the conductivetip 110 in the housing 180, a receiver 130 and a driver 140 that areconnected to the switching unit 120 in parallel, a signal processor 150that receives and processes a reception signal from the receiver 130 toperform synchronization, a power supply source 160 that is connected tothe signal processor 150 to supply power, and an input/output (I/O)interface 170 that is connected between the signal processor 150 and thepower supply source 160.

The conductive tip 110 may be formed of a conductive material such asmetal and/or the like and may be time-divided to act as a receptionelectrode and a transmission electrode. When the conductive tip 110touches the display panel 200, the conductive tip 110 may be coupled toa touch electrode COMx, which overlaps the conductive tip 110 or is themost adjacent to the touch tip 110, among the touch electrodes includedin the touch screen and may receive the touch electrode driving signalfrom a corresponding touch electrode or may transfer a pen outputsignal, output from the touch pen, to the touch screen.

For example, in the display panel 200, a polarizer or a passivationlayer may be disposed on an uppermost side. The polarizer or thepassivation layer may function as an insulation layer to generate asensing capacitance Csen between the conductive tip 110 and the touchelectrode. When the conductive tip 110 touches the display panel 200,the conductive tip 110 may change a value of the sensing capacitanceCsen which is constant on a corresponding touch electrode, and the touchdriving circuit may read a change in the value of the sensingcapacitance Csen to detect a touched position.

When the touch pen 100 touches the display panel 200, the switching unit120 may be directly and electrically connected to the conductive tip110, and the conductive tip 110 may determine whether to act as thereception electrode or the transmission electrode.

The receiver 130 may amplify and process a signal received through theconductive tip 110. Here, the signal received from the conductive tip110 may correspond to the touch electrode driving signal Ts applied to atouch electrode which is provided in an area touched by the touch pen.

In an initial state, the touch pen may be turned on, and then, when thetouch pen touches the display panel 200, the conductive tip 110 may bedirectly connected to the receiver 130 through the switching unit 120.Then, the receiver 130 may amplify the received touch electrode drivingsignal Ts by using an amplifier included therein to supply the amplifiedtouch electrode driving signal Ts to the signal processor 150.

The signal processor 150 may analyze a signal supplied through thereceiver 130 to generate a synchronization signal synchronized with thetouch electrode driving signal Ts and may supply the touch electrodedriving signal Ts to the driver 140.

The driver 140 may include a level shifter. The driver 140 may generatea pen output signal Ps, which swings between a predetermined highvoltage and a predetermined low voltage, in synchronization with thetouch electrode driving signal Ts. Also, the driver 140 may supply thegenerated pen output signal Ps to the conductive tip 110 through theswitching unit 120.

The housing 180 may include the power supply source 160 and the I/Ointerface 170. Turn-on driving of the touch pen 100 may be controlledthrough the I/O interface 170. The I/O interface 170 may be connected tothe power supply source 160 included in the housing 180 to supplynecessary power to the receiver 130, the driver 140, and the signalprocessor 150.

Here, the I/O interface 170 may be electrically connected to the powersupply source 160 according to a pressing operation performed by a user,and an operation of the touch pen may be controlled according to thepressing operation.

FIG. 8 is a flowchart illustrating an operation of the touch penaccording to an embodiment of the present invention.

First, in operation 10S, the power supply source 160 may supply power tothe touch pen 100 through the I/O interface 170.

Subsequently, in operation 20S, the conductive tip 110 may touch acertain portion of the display panel 200.

In operation 30S, the conductive tip 110 may be immediately coupled tothe touch electrode included in the display panel 200 at an initialtouch time and may sense a touch electrode driving signal received fromthe touch electrode of the touch screen to transfer the touch electrodedriving signal to the receiver 120.

In operation 40S, the receiver 120 may amplify a received signal and maytransfer the amplified signal to the signal processor 150, and thesignal processor 150 may find a timing synchronized with a signaltransferred from the touch electrode. In this case, the signal processor150 may include a comparator. The comparator may compare a predeterminedthreshold value with the amplified signal input thereto, and when thethreshold value is lower than the amplified signal, the signal processor150 may determine whether there is a touch.

The signal processor 150 may analyze the signal supplied from thereceiver 120 and may set a timing between the received touch electrodedriving signal and the pen output signal Ps which is to be transferred.Also, the signal processor 150 may generate a synchronization signalaccording to a result of the setting and may supply the synchronizationsignal to the driver 140. An operation of generating the synchronizationsignal may be performed in, for example, one frame or more periods.

The reason that the one frame or more periods are set for the signalcorrection is for sufficiently correcting a phase difference between thereceived touch electrode driving signal Ts of the touch screen and thepen output signal Ps.

All of one frame may not actually be used for a touch operation. The oneframe may be divided into the pixel array driving period T1 and thetouch screen driving period T2, and during only the touch screen drivingperiod T2, the touch electrode driving signal may be received from thetouch screen. Therefore, in signal correction performed by the signalprocessor 150, the touch electrode driving signal may be sufficientlyreceived in one frame or more periods, and then, a synchronizationtiming of the pen output signal Ps may be determined.

When a phase error between the touch electrode driving signal Ts and thepen output signal Ps is greater than a default value, a separatecorrection algorithm may be further executed.

Subsequently, in operation 50S, the driver 140 may synchronize the penoutput signal Ps having a predetermined frequency and amplitudeaccording to the synchronization signal supplied from the signalprocessor 150.

Subsequently, in operation 60S, the driver 140 may supply the generatedpen output signal Ps to the conductive tip 110 through the switchingunit 120.

The touch pen may touch the touch screen after an initial turn-onoperation of the touch pen, and then, a switching period may be providedbetween a reception period Rx of the touch electrode driving signal Tsand a transmission period Tx where the pen output signal Ps istransferred to the touch screen. The switching period may be a periodwhere the signal processor 150 corrects a signal.

In subsequent frames, an operation Tx of transferring through theconductive tip the pen output signal Ps synchronized with the touchelectrode driving signal Ts and an operation Rx of receiving a drivingsignal of the touch screen by using the conductive tip may be repeatedlyperformed through time division. An initial pen output signal Ps may besynchronized with the touch electrode driving signal Ts, and then, insubsequent frames, a switching period between a reception period Rx anda transmission period Tx of pen driving may be omitted, and driving maybe performed by time-dividing the reception period and the transmissionperiod in a touch sensing period.

Hereinafter, a configuration and a method for synchronizing the penoutput signal Ps with the touch electrode driving signal Ts will bedescribed in more detail.

FIG. 9 is a driving waveform diagram showing the touch electrode drivingsignal Ts and the pen output signal Ps.

Referring to FIGS. 7 and 9, the touch electrode driving signal Ts mayinclude a first touch electrode driving signal Ts1 and a second touchelectrode driving signal Ts2.

The touch electrode driving signal Ts1 may be output only once at aninitial stage of each of a plurality of frames. Also, the second touchelectrode driving signal Ts2 may be repeatedly output at every certainperiod after the first touch electrode driving signal Ts1 is output.

The first touch electrode driving signal Ts1, as illustrated in FIG. 10,may be a signal for determining whether there is a touch which isperformed for a setting unit OP which is provided on each of both sidesof a home button HO in a portable electronic device such as a smartphoneor the like.

When the multiplexer 302 illustrated in FIG. 5 is provided in plurality,the second touch electrode driving signal Ts2 may be signals which areapplied to the touch electrodes COM1 to COMn through the plurality ofmultiplexers 302.

For example, the first touch electrode driving signal Ts1 may include Nnumber of pulses. Also, the second touch electrode driving signal Ts2may include M number of pulses different from the N pulses. Here, N maybe less than M.

The signal processor 150 of the touch pen may output a synchronizationsignal according to the first touch electrode driving signal Ts1. Then,the driver 140 of the touch pen may generate the pen output signal Psincluding the M pulses having the same frequency as that of the secondtouch electrode driving signal Ts2 and may adjust an output time of thepen output signal Ps which is generated according to the synchronizationsignal.

That is, the signal processor 150 may control the driver 140 in orderfor an output of the pen output signal Ps to start after a predeterminedtime elapses from a time CT when the N pulses included in the firsttouch electrode driving signal Ts1 are all counted.

Therefore, the pen output signal Ps which is generated and output by thedriver 140 of the touch pen may have the same frequency and phase asthose of the second touch electrode driving signal Ts2.

The touch pen according to the embodiments of the present invention isproposed to be applied to a capacitive touch screen device proposed bythe applicant. For example, the present invention is proposed in orderfor an active touch pen to be applied to an in-cell type touch screendevice disclosed in Korean Patent Publication Nos. 10-2014-0105216,10-2014-0085995, and 10-2014-0083214 proposed by the applicant.Therefore, the touch pen according to the embodiments of the presentinvention may be applied to the touch screen device disclosed in theabove-described reference documents.

As described above, according to the embodiments of the presentinvention, the conductive tip of the touch pen may be used as an elementthat receives the touch electrode driving signal of the touch screen.Also, the conductive tip may be used as an element that transmits a penoutput signal generated in the touch pen. Also, the touch pen may outputthe pen output signal in synchronization with the touch electrodedriving signal of the touch screen which is received by the touch pen.

Therefore, according to the embodiments of the present invention,whether a touch is performed by the touch pen is accurately detected inthe driving period of the touch screen, and thus, an accuracy of touchdetection increases. Accordingly, it is possible to implement ahigh-sensitivity input pen. Also, a linearity of touch detection ismaintained, and thus, touch performance is enhanced. Also, although aseparate electrode for driving the touch pen is not added into thedisplay panel, a high sensation of touch sensing is maintained, andthus, a structure is simplified.

It will be apparent to those skilled in the art that variousmodifications and variations can be made in the present inventionwithout departing from the spirit or scope of the inventions. Thus, itis intended that the present invention covers the modifications andvariations of this invention provided they come within the scope of theappended claims and their equivalents.

What is claimed is:
 1. A touch screen device comprising: a touch screenincluding a plurality of touch electrodes; a touch driving circuitapplying a touch electrode driving signal to the plurality of touchelectrodes; and a touch pen receiving the touch electrode driving signalapplied to the plurality of touch electrodes and transmitting a penoutput signal, synchronized with the received touch electrode drivingsignal, to the touch screen.
 2. The touch screen device of claim 1,wherein the touch pen comprises: a conductive tip, a portion of theconductive tip protruding to one side of a housing; a switching unitconnected to the conductive tip; a receiver amplifying, processing, andoutputting the touch electrode driving signal received through theswitching unit; a signal processor analyzing a signal supplied from thereceiver to output a synchronization signal for synchronizing the penoutput signal with the touch electrode driving signal; and a drivergenerating the pen output signal according to the synchronization signalto supply the pen output signal to the switching unit.
 3. The touchscreen device of claim 2, wherein the touch electrode driving signalcomprises a first touch electrode driving signal including N number ofpulses and a second touch electrode driving signal including M number ofpulses different from the N pulses.
 4. The touch screen device of claim3, wherein the signal processor outputs the synchronization signalaccording to the first touch electrode driving signal, and the drivergenerates the pen output signal including the M pulses having the samefrequency as a frequency of the second touch electrode driving signaland adjusts an output time of the pen output signal which is generatedaccording to the synchronization signal.
 5. The touch screen device ofclaim 4, wherein the signal processor controls the driver for an outputof the pen output signal to start after a predetermined time elapsesfrom a time when the N pulses included in the first touch electrodedriving signal are all counted.
 6. The touch screen device of claim 2,wherein the touch electrode driving signal is output once at an initialstage of each of a plurality of frames, and the second touch electrodedriving signal is repeatedly output at every certain period after thefirst touch electrode driving signal is output.